1. Technical Field of the Invention
The present invention relates to a machining apparatus and method for machining long workpiece having a constant sectional shape.
2. Description of the Related Art
Various workpieces of continuous lengths, which have constant section shape, have been used as general building workpieces such as an aluminum sash. In this application such workpieces of continuous lengths are referred as “long workpieces”.
Patent Documents 1 and 2 disclose examples of apparatuses that process long workpieces such as I-beams and H-section steel.
The rotatable handling device in Patent Document 1 is constituted of positioning units 50, 51 for supporting the proximities of the ends of an I-beam 54, as shown in FIG. 1. The positioning unit 50 is attached to the top of a driving roller unit 53. The positioning unit 51 is attached to the top of a driven roller unit 54 that is in contact with the driving roller, and the positioning unit 51 rotates in synchronization with the frictional force.
The “Supporting Apparatus for Structural Steel” in Patent Document 2 comprises a base 61, supporting rollers 66, 67 disposed on top of the base, a ring-shaped frame 68 that is rotatably mounted on these supporting rollers and that can be opened and closed at one part, a rotation drive mechanism that fits over the external periphery of the ring-shaped frame and that rotates the ring-shaped frame, and a mechanism that is provided on the inside of the ring-shaped frame and that supportably fixes H-section steel or other such structural steel in the center of the ring-shaped frame, as shown in FIG. 2.
Patent Documents 3 and 4 have already disclosed examples of machining apparatuses for continuous-length, irregularly shaped workpieces, such as aluminum sashes.
The “Fixing Method and Apparatus for workpiece” in Patent Document 3 comprises a holding plate 74 for holding workpiece, and a clamper 75 for pressing down on the workpiece, wherein the clamper 75 comprises a pressing part 71 that moves back and forth in relation to the holding plate and presses down on the workpiece, and the pressing part 71 is a balloon, as shown in FIG. 3.
The “MACHINING APPARATUS AND EQUIPMENT OF THIN SECTION LONG WORKPIECE” in Patent Document 4 comprises a workpiece clamp device 80 for horizontally holding the thin section long workpiece. This thin workpiece either has a constant sectional shape or has the same sectional shape at intervals in a longitudinal direction. This workpiece clamp device 80 is constituted of a driving clamp device 80A and a driven clamp device 80B that both have a holding device 82, wherein the driving clamp device rotatably drives the thin section long workpiece around a horizontal axis O extending in the length direction, and the driven clamp device is driven by the thin section long workpiece to idle around the horizontal axis.
[Patent Document 1]
U.S. Pat. No. 3,521,875 Specification, “Rotatable Handling Device”
[Patent Document 2]
Utility Model Application No. 54-148285, “Supporting Apparatus for Structural Steel”
[Patent Document 3]
Japanese Patent Application Laid-open No. 10-156651 “Fixing Method and Apparatus for workpiece”
[Patent Document 4]
Japanese Patent Application Laid-open No. 2002-301631 “Machining Apparatus and Machining Equipment for Thin Section Long Workpiece”
The conventional long workpiece machining apparatuses described above have the following problems.    (1) With the apparatuses in Patent Documents 1 and 2, an exclusive-use jig that matches the sectional shape of the workpiece is needed to fix the workpiece in place.    (2) With the apparatus in Patent Document 3, about ¼ of the frame 77 and the rotor 78 is cut out, and it is therefore impossible to process about ¼ of the article with each rotation. Therefore, the workpiece must be rotated in the reverse direction in cases in which the entire periphery must be machined.    (3) With the apparatus in Patent Document 4, the entire periphery can be machined without reverse rotation, but since workpieces must be conveyed in and out in the longitudinal direction, the workspace must have about twice the length of one workpiece.    (4) With the apparatuses in Patent Documents 1 through 4, the held portions of the workpieces interfere with the holding devices and the machining apparatus, making it difficult to machine the held portions as such, and making machining impossible at least in automatic operation.